Why didnt the writers car start?

Read the passage below and choose one correct answer for each question.

AN UNLUCKY DAY

       Last Sunday was definitely not a good day for me. It all started when I got into my car and it refused to start. I immediately realized that I had left the lights on and the battery had gone flat. I telephoned my friend George and he came round and helped me start the car. I then drove into town to see a friend. I had arranged to meet him at six thirty, but by the time I got there, it was ten past seven and my friend was not there. I waited for him for an hour despite the freezing weather, but he didn't come. When I returned to my car, I saw that someone had broken into it, probably looking for the radio. Luckily, I never leave the radio in the car! There was nothing I could do but get into my car and drive home. Later, I spoke with my friend and discovered that he had waited for only half an hour and left. He didn't even apologize for not waiting for me longer!

Why didn't the writer's car start?

• A. Because it hadn't been serviced.
• B. Because the lights had gone wrong.
• C. Because the battery had gone flat.
• D. Because the battery had been stolen.